Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 40: Poster II: Bio- and Molecular Magnetism (1-9); Magnetic Coupling Phenomena/Exchange Bias (10-15); Magnetic Particlicles and Clusters (16-29); Micro and Nanostructured Magnetic Materials (30-51); Multiferroics (52-64); Spin Injection in Heterostructures (65-67); Spin-Dyn./Spin-Torque (68-93); Spindependent Transport (94-108)
MA 40.92: Poster
Freitag, 27. März 2009, 11:00–14:00, P1A
Effect of a DC current on the magnetization dynamics in spin-valve nanocontacts — •Abdelghani Laraoui1, Florin Ciubotaru1, Helmut Schultheiß1, Alexander Serga1, Sebastian Hermsdörfer1, Maarten van Kampen2, Liesbet Lagae2, Britta Leven1, Andrei N. Slavin3, and Burkard Hillebrands1 — 1Fachbereich Physik and Forschungszentrum OPTIMAS, TU Kaiserslautern, 67663 Kaiserslautern, Germany — 2IMEC, Kapeldreef 75, Leuven, Belgium — 3Oakland University, Rochester, Michigan, USA
We have studied the magnetization dynamics in spin-valve nanocontact devices under the influence of an applied microwave ac and dc current by means of Brillouin light scattering (BLS) microscopy. To obtain an idea of the possible modes of spin waves that can be excited, the 80 nm point contact was subjected to an ac current of varying frequencies and powers. The BLS spectra of the extended Py free layer of the spin-valve stack were recorded at a fixed position near to the point contact (~ 200 nm) and for various amplitudes of an external magnetic field. Strong nonlinear spin waves are excited with the ac current and discussed within the framework of three magnon scattering. In the presence of a dc current the efficiency of the direct excited modes is enhanced. This effect can be explained by both spin transfer torque and Oersted field effects. In addition, the threshold properties for nonlinear spin-waves (non-integer modes) excitation are mainly controlled by the Oersted field created by the dc current injected through the nanocontact. Support by EU-MRTN SPINSWITCH (MRTN-CT-2006-035327) and by the Deutsche Forschungsgemeinschaft (SPP1133).